Japanese Patent No. 3868892 discloses a top sheet for absorbent articles, which is a nonwoven fabric having multiple heat-fused sections formed by embossing, wherein the fibers composing the nonwoven fabric between the heat-fused sections protrude in the direction of thickness of the nonwoven fabric, forming multiple elevated sections on the upper and lower sides. It further discloses that the nonwoven fabric has an upper layer and an adjacent lower layer, and discloses a production process wherein a lower layer containing at least 50 wt % latent crimping fiber is laminated with and an upper layer containing heat sealing fiber that either has essentially no heat shrinking property or undergoes no heat shrinkage at below the initial crimp temperature of the latent crimping fiber, and the laminate from the lower layer side is embossed to partially bond both webs by the multiple heat-fused sections to form a nonwoven fabric, after which the latent crimping fiber located around the heat-fused sections of the lower layer are pre-crimped and then the nonwoven fabric is heat treated at a temperature above the initial crimp temperature of the latent crimping fiber to shrink the lower layer, causing the upper layer and lower layer to protrude in the direction of thickness of the nonwoven fabric to form numerous elevated sections.
Japanese Unexamined Patent Publication No. 2004-181086 discloses an absorbent article wherein the top sheet comprises heat sealable fiber, a second layer containing heat sealable fiber is provided below the top sheet, the top sheet and second layer are compressed together and the top sheet and second layer fused together, and states that the absorbent article is produced by inserting the top sheet and second layer between heated rolls to form embossed sections, during which time a roll with a flat surface is placed against the surface of the second layer and an embossing roll on which protrusions have been formed in the surface is placed against the top sheet side (paragraph [0068]), and the cross-section of the article obtained in this manner shows a structure with irregularities on the front side and a flat rear side, wherein the fused sections where the top sheet and second layer have been fused are located at the lowermost section in the thickness direction (FIG. 4).